Advances in sequencing, bioinformatics and analytics now allow the structure, function and interrelations of whole microbial communities to be studied in greater detail. Collaborative efforts and multidisciplinary studies, crossing the boundary between environmental and medical microbiology, have allowed specific environmental, animal and human microbiomes to be characterized. One of the main challenges for microbial ecology is to link the phylogenetic diversity of host-associated microbes to their functional roles within the community. Much remains to be learned on the way microbes colonize the skin of different living organisms and the way the skin microbiome reacts to the surrounding environment (air, water, etc.). In this review, we discuss examples of recent studies that have used modern technology to provide insights into microbial communities in water and on skin, such as those in natural resources (thermal spring water), large mammals (humpback whales) and humans (the skin microbiome). The results of these studies demonstrate how a greater understanding of the structure and functioning of microbiota, together with their interactions with the environment, may facilitate the discovery of new probiotics or postbiotics, provide indicators for the quality of the environment, and show how changes in lifestyle and living environment, such as urbanization, can impact on the skin microbiome and skin health and disease in humans.

BackgroundAtopic dermatitis (AD) is a common skin disease characterized by recurrent pruritic inflammatory skin lesions resulting from structural and immune defects of the skin barrier. Previous studies have shown the clinical efficacy of Avène thermal spring water in AD, and a new microorganism, Aquaphilus dolomiae was suspected to contribute to these unique properties. The present study evaluated the anti-inflammatory, antipruritic, and immunomodulatory properties of ES0, an original biological extract of A. dolomiae, in immune and inflammatory cell models in order to assess its potential use in the treatment of AD.Materials and methodsAn ES0 extract containing periplasmic and membrane proteins, peptides, lipopolysaccharides, and exopolysaccharides was obtained from A. dolomiae. The effects of the extract on pruritus and inflammatory mediators and immune mechanisms were evaluated by using various AD cell models and assays.ResultsIn a keratinocyte model, ES0 inhibited the expression of the inflammatory mediators, thymic stromal lymphopoietin, interleukin (IL)-18, IL-4R, IL-8, monocyte chemoattractant protein-3, macrophage inflammatory protein-3α, and macrophage-derived chemokine and induced the expression of involucrin, which is involved in skin barrier keratinocyte terminal differentiation. In addition, ES0 inhibited protease-activated receptor-2 activation in HaCaT human keratinocytes stimulated by stratum corneum tryptic enzyme and T helper type (Th) 1, Th2, and Th17 cytokine production in Staphylococcal enterotoxin B–stimulated CD4+ lymphocytes. Lastly, ES0 markedly activated innate immunity through toll-like receptor (TLR) 2, TLR4, and TLR5 activation (in recombinant human embryonic kidney 293 cells) and through antimicrobial peptide induction (psoriasin, human beta-defensin-2, and cathelicidin), mainly through TLR5 activation (in normal human keratinocytes).ConclusionOverall, these in vitro results confirm the marked regulatory activity of this A. dolomiae extract on inflammatory and immune responses, which may be of value by virtue of its potential as an adjunctive treatment of AD inflammatory and pruritic lesions.

Respiratory syncytial virus (RSV) is an important cause of severe upper and lower respiratory disease in infants and in the elderly. There are 2 main RSV subtypes A and B. A recombinant vaccine was designed based on the central domain of the RSV-A attachment G protein which we had previously named G2Na (aa130–230). Here we evaluated immunogenicity, persistence of antibody (Ab) response and protective efficacy induced in rodents by: (i) G2Na fused to DT (Diphtheria toxin) fragments in cotton rats. DT fusion did not potentiate neutralizing Ab responses against RSV-A or cross-reactivity to RSV-B. (ii) G2Nb (aa130–230 of the RSV-B G protein) either fused to, or admixed with G2Na. G2Nb did not induce RSV-B-reactive Ab responses. (iii) G2Na at low doses. Two injections of 3 µg G2Na in Alum were sufficient to induce protective immune responses in mouse lungs, preventing RSV-A and greatly reducing RSV-B infections. In cotton rats, G2Na-induced RSV-reactive Ab and protective immunity against RSV-A challenge that persisted for at least 24 weeks. (iv) injecting RSV primed mice with a single dose of G2Na/Alum or G2Na/PLGA [poly(D,L-lactide-co-glycolide]. Despite the presence of pre-existing RSV-specific Abs, these formulations effectively boosted anti-RSV Ab titres and increased Ab titres persisted for at least 21 weeks. Affinity maturation of these Abs increased from day 28 to day 148. These data indicate that G2Na has potential as a component of an RSV vaccine formulation.